Adaptive Topology Optimization Of Heat Transfer Structures By Optimality Criteria

With the decrease of the volume of electronic products,the integration of their internal components increases seriously.When a lot of heat is generated inside the products,it determines the performance and service life of the products whether the heat can be dissipated in time from their interior.So,the efficient heat dissipation is the key technology of the products that should be further developed.Because of the concentrative heat sources and the restricting heat dissipation space,the traditional convection heat dissipation of electronic products can't attain actual requirement of heat dissipation.There is the effective way of solving the problem.The heat dissipation channel formed by the high thermal conductivity material is laid on the surface of the components or directly embedded in the components.As the heat is quickly transferred into the external environment,the problem of space constraint and heat dissipation efficiency can be solved.The technology of structural topology optimization design can be used in the heat dissipation channel design.The technology can effectively solve the complex heat transfer problems and get the reasonable topological configuration of the heat dissipation channel.The shape of heat dissipation channel designed by the current topology optimization design of heat transfer structure is excessively complicated.There are also some problems of the numerical instabilities in the design results,such as checkerboard phenomenon and gray level units.These problems affect the application value of design results in practical engineering.In this paper,Aiming at the problems in the current topology optimization design of the heat transfer structure,a new method of adaptive topology optimization of heat transfer structure by optimality criteria is proposed based on the study of the mechanism of plant root growth,bifurcation and degradation.The paper focuses on the following contents.The construction technology of ground structure that is suitable for adaptive topology optimization problems of heat transfer structure is studied.The ground structures of two-dimensional plate structure under the non-uniformly thermal load working condition and the concentrated thermal load working condition and the three-dimensional shell structure are established.Based on the Kuhn-Tucker optimal criterion condition,mathematical model is solved and the iterative formula of the optimal criterion method is derived.The cross sectional areas of the bar units are selected to be the design variables and the minimum of dissipation of heat transport potential capacity is the design objective.The heat transfer channels of typical two-dimensional and three-dimensional design problems are studied and the designed results are compared with optimization results of COMSOL software to verify the correctness of the proposed method.In order to illustrate the accuracy of the design method and provide the reference range of parameters value in practical engineering,the influence of the key parameters on the design results is analyzed,such as initial value of the design variable,penalty coefficient and volume constraint factor.The results show that the adaptive topology optimization method of heat transfer structure by optimality criteria can be used on two-dimensional and three-dimensional heat transfer structure design and the produced layout of the heat dissipation channel is simple and clear and its heat transfer capability is better.Moreover,the suggested method is more effective than other methods in the rate of convergence.The problems of numerical instabilities happened in current optimization methods are successfully solved by the adaptive topology optimization method of heat transfer structure.Based on the VB advanced program language,the adaptive topology optimization software of heat transfer structure is designed by the secondary development of ANSYS software.With a friendly user interface,the software can be operated conveniently.It also further improves the applicability of adaptive topology optimization method of heat transfer structure by optimality criteria.